These years, an employment of permanent magnet type rotary electric machines is increasing remarkably in respective fields with respect to rotary electric machines. And in order to enhance economy through increasing a single machine capacity of permanent magnet type rotary electric machine, a demand of a small size and large capacity permanent magnet type rotary electric machine is increasing. However, when reducing the size and increasing the capacity of a permanent magnet type rotary electric machine is tried, since the amount of heat generated is increased, a permanent magnet type rotary electric machine as shown in FIG. 1 in patent document 1 has been proposed in which cooling use ventilation passages are formed between respective magnetic poles.
Through forming the cooling use ventilation passages between respective magnetic poles, the amount of heat generated can be suppressed, and the size of the permanent magnet type rotary electric machine can be reduced corresponding to the suppression. However, due to the formation of the cooling use ventilation passages between respective magnetic poles, magnetic flux concentration to the respective magnetic poles becomes remarkable, which causes to increase torque ripple that leads to increase such as vibrations and noises.
In order to decrease this magnetic flux concentration to the respective magnetic poles, an air gap between the outer circumferential face of the magnetic pole and the stator is increased at both end portion sides in circumferential direction in comparison with that at the center portion of the magnetic pole as shown FIGS. 14 and 15 in the patent document 11, thereby, the magnetic flux concentration is relaxed, and the torque ripple is reduced.
Patent Document 1: JP-A-2008-131813